Greywater Treatment & Reuse: Nature-Based Solutions Explained

This resource details greywater treatment and reuse strategies, emphasizing nature-based solutions (NBS) like constructed wetlands, green roofs, and green walls for household and building-scale applications. Greywater from baths, sinks, and washing machines is treated via diversion/filtration, chemical methods, or NBS, yielding environmental, economic, and energy benefits. Systems suit new builds or retrofits. Key methods: biofilters remove fats/oils, followed by sand/gravel for particulates. NBS examples include multi-level green walls/façades with mechanical filters and activated carbon, plus O3/UV disinfection. Pilots: Houseful project tested indoor/outdoor green wall modules for greywater, with ozone/UV final steps and a leasing service model (fee per m³ treated). UNaLab piloted water management platforms for monitoring. NAWAMED used green walls/constructed wetlands for public buildings, parking, and refugee camps. Practical steps: (i) separation, (ii) storage, (iii) NBS treatment, (iv) disinfection. Benefits include nutrient recovery, reduced freshwater use, and urban resilience. The guide cites studies on efficiency, providing specifics for decentralized implementation, pilot outcomes, and scalable models for practitioners in urban settings.